scholarly journals Observation of transition cascades in sheared liquid crystalline polymers

Soft Matter ◽  
2020 ◽  
Vol 16 (16) ◽  
pp. 3891-3901 ◽  
Author(s):  
Ryan J. Fox ◽  
M. Gregory Forest ◽  
Stephen J. Picken ◽  
Theo J. Dingemans
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Shear Thickening ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Crystalline Polymers ◽  
Nematic Director ◽  
Thickening Behavior

We observe anomalous shear thickening behavior of a lyotropic liquid crystalline polymer due to the dynamics of the nematic director.

Research and Development of Functional Fluid Mechatronics, Rehabilitation Systems, and Mechatronics of Flexible Drive Systems

2016 ◽  
Vol 28 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Junji Furusho ◽  
◽  
Naoyuki Takesue ◽  
Keyword(s):  
Research And Development ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Magnetorheological Fluid ◽  
Servo Drive ◽  
Crystalline Polymers ◽  
Upper And Lower Extremities ◽  
Drive Systems

[abstFig src='/00280001/01.jpg' width=""260"" text='PLEMO-P3 Developed by Furusho Lab at Osaka Univ.' ]We conducted many research and development activities on functional fluid mechatronics, rehabilitation systems, and servo drive systems. In this review, studies on the development of magnetorheological fluid devices, electrorheological effects of liquid crystalline polymers on one-sided pattern electrodes, and vibration control using control theory and liquid crystalline polymer are introduced. In addition, applications of rehabilitation systems for upper and lower extremities employing functional fluids for individuals suffering from stroke, cerebellar ataxia, and Guillain-Barre syndrome are also introduced.

Synthesis and Performance of a Novel Coumarin-Containing Side-Chain Liquid Crystalline Polymer

2011 ◽  
Vol 181-182 ◽  
pp. 197-200
Author(s):  
Yu Lei Zhao ◽  
Wei Min Zhang ◽  
Ji Lei Li ◽  
Fan Fan Yu ◽  
Jia Ling Pu
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Polarized Optical Microscopy ◽  
Crystalline Polymers ◽  
New Type ◽  
And Performance ◽  
Thermal Stability Of

A new type of able liquid crystalline polymer with a coumarin-containing mesogenic side group that could be photo-crosslinked was synthesized in this paper. The structure of the intermediates, monomers and polymers were characterized with FTIR and 1HNMR measurement. DSC, TG, and hot stage polarized optical microscopy were employed to study the phase transition temperature, mesophase texture, and thermal stability of the liquid crystalline polymers. The results indicated that both the monomer and polymer exhibited liquid-crystalline features over a wide temperature range.

Photochemistry of Azobenzene Side-Chains Liquid Crystalline Containing Pendant Polyhedral Oligomeric Silsequioxanes (POSS)

2013 ◽  
Vol 721 ◽  
pp. 316-319
Author(s):  
Xiao Tao Wang ◽  
Xiao Tie Ye ◽  
Zhen Hua Li ◽  
Zui Fang Liu
Keyword(s):  
Thermal Stability ◽  
Rate Constant ◽  
High Performance ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Side Chains ◽  
Crystalline Polymers ◽  
First Order

Liquid crystalline polymer (LCP) and the copolymer of LCOand Pendant Polyhedral Oligomeric Silsequioxanes (LCP-POSS) showed the first-order photoisomerization reaction. As compared with LCP, the photoisomerization rate constant of LCP-POSS decreased a little. With a higher thermal stability and more stable LC behavior as well as a little decreased photoisomerization rate constant, the incorporation of POSS to azobenzene liquid crystalline polymers may have significant sense and will definitely play a key role in developing novel high-performance optic and photonic nanodevices.

scholarly journals Bending Behaviors of Azobenzene-containing Liquid Crystalline Polymers (AZ-LCP): Factors Influencing Bending Direction, Frequency and Degree

2021 ◽  
Vol 294 ◽  
pp. 05004
Author(s):  
Yin junyi
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Liquid Crystal Polymers ◽  
Mechanical Motion ◽  
Internal Factors ◽  
Crystalline Polymers ◽  
Factors Influencing ◽  
Soft Actuators

Liquid crystal polymers (LCP) containing azobenzene and its derivatives are fascinating and topics of intense scientific curiosities. As the addition of photo-responsive azobenzene, the LCP is exerted with the photochemical response, which shows fascinating and useful photo-induced motions and consequently enables a variety of applications in a lot of fields. In this review, we detail the macroscale mechanical motion of azobenzene containing liquid crystalline polymer (AZ-LCP) materials upon irradiation, with emphasis on the external and internal factors of bending behaviors of AZ-LCP, including bending direction, frequency and degree. We end with an outlook of challenging and competitive application as soft actuators.

Self organization of main-chain/side-chain liquid crystalline polymer based on “jacketing” effect with different lengths of spacer: from smectic to hierarchically ordered structure

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97187-97194 ◽  
Author(s):  
He-lou Xie ◽  
Bin Ni ◽  
Quan Liu ◽  
Jun Wang ◽  
Shuang Yang ◽  
...  
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Main Chain ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Self Organization ◽  
Side Chain ◽  
Ordered Structure ◽  
Organization Behavior ◽  
Crystalline Polymers

A series of combined main-chain/side-chain liquid crystalline polymers based on the “jacketing” effect, with different alkyl spacer lengths (n = 2–10), have been successfully synthesized and their self-organization behavior has been investigated.

Structure-property relations of liquid crystalline polymers

1987 ◽  
Vol 45 ◽  
pp. 460-463
Author(s):  
Linda C. Sawyer
Keyword(s):  
Solid State ◽  
Liquid Crystalline ◽  
Structural Model ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Mechanical Anisotropy ◽  
Structure Property ◽  
Preparation Methods ◽  
Crystalline Polymers ◽  
Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

Photoinduced Bending Behaviour of Cross-linked Liquid Crystalline Polymers with High Cross-linking Densities

2014 ◽  
Vol 67 (4) ◽  
pp. 570 ◽  
Author(s):  
Zhen Jiang ◽  
Jiu-an Lv ◽  
Futao Chen ◽  
Jia Wei ◽  
Yanlei Yu
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Reverse Direction ◽  
Cross Linking ◽  
Side Chains ◽  
Material System ◽  
Crystalline Polymers ◽  
The Cross ◽  
Bending Behaviour

Highly cross-linked liquid crystalline polymer (CLCP) films with a long spacer and azobenzene chromophores (of varying concentrations and positioned differently) were prepared. The effects of various factors on the photoinduced bending behaviour of the highly CLCPs were explored. Long spacer groups and high cross-linking density resulted in considerably faster bending of the CLCP films relative to those reported in the literature that feature shorter spacer groups and smaller cross-linking densities. The azobenzene chromophores at the cross-linking points significantly influenced the photoinduced bending behaviour of the CLCP films relative to those at side chains. Furthermore, reduced concentrations of the azobenzene chromophores produced faster bending and larger photoinduced stress of the CLCP films that contained chromophores at the side chains as opposed to those incorporating chromophores at the cross-linking points. Moreover, the CLCP film with relatively low azobenzene concentration and small thickness exhibited bending in the reverse direction following maximum bending under continuous UV irradiation, thereby showing that photomobile behaviour of the material system.

scholarly journals Rheological signatures in limit cycle behaviour of dilute, active, polar liquid crystalline polymers in steady shear

2014 ◽  
Vol 372 (2029) ◽  
pp. 20130362 ◽  
Author(s):  
M. Gregory Forest ◽  
Panon Phuworawong ◽  
Qi Wang ◽  
Ruhai Zhou
Keyword(s):  
Limit Cycles ◽  
Soft Matter ◽  
Liquid Crystalline ◽  
Numerical Study ◽  
Shear Thickening ◽  
Liquid Crystalline Polymers ◽  
Two Dimensional ◽  
Crystalline Polymers ◽  
Link Type ◽  
Linearized Stability

We consider the dilute regime of active suspensions of liquid crystalline polymers (LCPs), addressing issues motivated by our kinetic model and simulations in Forest et al. (Forest et al. 2013 Soft Matter 9 , 5207–5222 ( doi:10.1039/c3sm27736d )). In particular, we report unsteady two-dimensional heterogeneous flow-orientation attractors for pusher nanorod swimmers at dilute concentrations where passive LCP equilibria are isotropic. These numerical limit cycles are analogous to longwave (homogeneous) tumbling and kayaking limit cycles and two-dimensional heterogeneous unsteady attractors of passive LCPs in weak imposed shear, yet these states arise exclusively at semi-dilute concentrations where stable equilibria are nematic. The results in Forest et al. mentioned above compel two studies in the dilute regime that complement recent work of Saintillan & Shelley (Saintillan & Shelley 2013 C. R. Physique 14 , 497–517 ( doi:10.1016/j.crhy.2013.04.001 )): linearized stability analysis of the isotropic state for nanorod pushers and pullers; and an analytical–numerical study of weakly and strongly sheared active polar nanorod suspensions to capture how particle-scale activation affects shear rheology. We find that weakly sheared dilute puller versus pusher suspensions exhibit steady versus unsteady responses, shear thickening versus thinning and positive versus negative first normal stress differences. These results further establish how sheared dilute nanorod pusher suspensions exhibit many of the characteristic features of sheared semi-dilute passive nanorod suspensions.

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